1. Field of the Invention
The present invention relates to a mold for horizontal continuous casting of steel, in particular for producing fiat products such as slabs. The mold includes a water-cooled metal casing forming a mold cavity for a slab and a breaking ring for the supply of melt. The breaking ring is supported at the mold on the pour-in side thereof and connects the mold with a melt supply vessel or distributor via a casting tube.
2. Description of the Related Art
In horizontal continuous casting plants, the molds are generally fastened to a side wall of a distributor. In many cases, the inlet cross section of a connecting part of first-class material between the distributor and mold is identical to the cross section of the mold (see DE-OS 25 20 091).
On the other hand, it is known from U.S. Pat. No. 3,593,778 to arrange a heat-conducting graphite plate having a plurality of through-flow openings between the distributor and a metal mold with a greater cross section than the feed channel of the distributor for the melt. In this way, heat is apparently conducted out of the melt in the transitional area between the distributor and mold to prevent cracks in the slab shell.
A more recent practice is to arrange a so-called break ring, preferably of boron nitride, between the feed nozzle and mold. The break ring is constructed in such a way that it forms the front boundary surface for the melt in the inlet region of the mold (see EP 0187 513 B1). The outer diameter of the breaking ring corresponds at least to the casting cross section of the mold and, as a result of its smaller inside diameter, forms a flange-like reduced diameter portion of the casting cross section of the mold. In contrast to the metal mold, this break ring is a part which is subject to wear and must be replaced frequently. However, break rings of boron nitride are expensive to produce and in large-site casting cross sections are costly and not very mechanically stable.